Expansion anchor

Abstract

An axially extending expansion anchor or dowel has an anchor body (2) with a first end region to be inserted first into a borehole (B) in a receiving material (G) and a trailing second end region in which a load can be applied. The first end region has an axially extending expansion region with at least two expanding tangs (7) separated from one another by axially extending slots. The first end region has a opening (11) into which an expanding body (12) is displaceable axially for radial expansion of the tangs (17). The axially extending opening (11) has an inner axially extending surface (10) closer to the axis of the anchor body and formed by a guide pin (9) of the anchor body (2) and an outer axially extending surface formed by the inner surface of the tangs (7). The expanding body (12) is basically sleeve-like shaped and has an inner surface which bears against the inner surface (10) of the opening (11). The outer surface of the expanding body (12) is, at least in part, wedge shaped. In the radially outwardly expanded state of the tangs (7), the expanding body (11) lies substantially flat against the inner and outer surfaces of the opening (11).

We claim: 
     
       1. An expansion anchor comprising an axially extending anchor body (2) having an axis, an axially extending first end section to be inserted into a bore hole (B) in a receiving material (G) and an opposite axially extending second end section (3) and a circumferential periphery, a load application means (4) is located in said second end section in said anchor body, said anchor body has an axially extending expansion region (6) in said first end section, said expansion region (6) has at least two axially extending tangs (7) separated from one another, said anchor body (2) has an axially extending recess in said first end section, an axially extending expanding body (12) is arranged to be inserted into and be axially displaced in said recess toward said second end section (3), said recess comprises at least one axially extending opening (11) with at least two sections each corresponding to one said tang having an inner surface closer to the axis of said anchor body and an outer surface more remote from the axis of said anchor body than said inner surface, said inner surface being formed by an outer surface (10) of an axially extending guide pin (9) in said first end region of said anchor body and said outer surface of said opening being formed by an inner surface (8) of said tangs (7) facing inwardly toward the axis of said anchor body, said expanding body (12) has an axially extending sleeve-like form with a inwardly facing surface (13) and an outwardly facing surface (14), said inwardly facing surface (13) extends along and contacts said outer surface (10) of said guide pin (9), said outwardly facing surface (14) of said expanding body (12) has wedge-shaped surfaces (15) extending in the axial direction, said expanding body arranged to expand said tangs (17) radially outwardly into an expanded state and, in the expanded state, said expanding body having said inwardly facing surface (13) in bearing contact with said inner surface of said opening (11) and said outwardly facing surface (14) being in bearing contact with said outer surface of said opening (11). 
     
     
       2. An expansion anchor, as set forth in claim 1, wherein said guide pin (9) in the expanded condition has a stressed cross-section comprising at least 25% of a sum of a stressed cross-sections of said expanding tangs (7) in the expanded condition. 
     
     
       3. An expansion anchor, as set forth in claim 1 or 2, wherein said load application means (4) is an one of an internal thread and an external thread of a threaded rod arranged to extend into a bore hole (5) in the second end section (3) of said expanding body (2), and said load application means (4) includes a connecting thread in said second end section (3) and said opening (11) having an axial dimension (d) in the range of 60% to 85% of a nominal diameter (n) of said connecting thread. 
     
     
       4. An expansion anchor, as set forth in claim 3, wherein said guide pin (9) has an axial length (l) at least equal to the axial depth (d) of said opening (11). 
     
     
       5. An expansion anchor, as set forth in claim 4, wherein the axial length (l) of said guide pin (9) corresponds to an axial length of said expanding body (11). 
     
     
       6. An expansion anchor, set forth in claim 1 or 2, wherein said opening (11) comprises at least two slots extending axially from a leading end of said anchor body (2) in said first end region and transversely of the axial direction end in axially extending strip-like slots in the circumferential periphery of said anchor body (2). 
     
     
       7. An expansion anchor, as set forth in claim 6, wherein said opening 11 has an equilateral triangle configuration in a plane extending transversely of the axial direction of said anchor body and is formed by three slots extending axially from a leading end of said anchor body (2) and has axially extending strip like opening in the circumferential periphery of said anchor body (2). 
     
     
       8. An expansion anchor, as set forth in claim 1 or 2, wherein said opening (11) for said expanding body (12) has a closed configuration in a plane extending transversely of the axial direction of said anchor body. 
     
     
       9. An expansion anchor, as set forth in claim 1 or 2, wherein said wedge surface (15) of said expanding body (12) encloses an angle (α) with the axis (A) of said anchor body (2) in the range of 5° to about 25°. 
     
     
       10. An expansion anchor, as set forth in claim 1 or 2, wherein said expanding body (12) has a leading end surface facing into said bore hole (B) of said receiving material (G) and said leading end surface is swept back from the inner surface (13) to the outer surface (14) of said expanding body and forms with the axis (A) of said anchor body (2) an angle (B) in the range of approximately 40° to 60°. 
     
     
       11. An expansion anchor, set forth in claim 1 or 2, wherein said anchor body (2) has an axially extending hole (5) in said second end section (3), said opening 11 has a passage (22) connected with said borehole (5), and said expanding body has a bracket-like axial extension (21) at a trailing end thereof facing said second end region whereby when said expanding body (12) is completely driven into said opening (11) said extension (21) projects through said passage (22) into said borehole (5).